Hi My name is Jean-Louis, ZS6AAG i am experimenting with uplink to the satellite with antenna logarithnic 12db, one hackrf and one ampli 2.4ghz 8 watts from china, can i attack directly the wifi amplifier or i need something between the hackrf and the wifi amplifier, many thanks for your answer

according to an article in the latest cqDL, we've ordered two LNBs from reichelt. With the cases open, we could see that they don't match the layout from the article, at all :-/

When powering it up, I cannot measure anything like 5 or 3.3 V, anywhere. Therefore we can see that the power supply is directly connected to the bug saying T101702 03 SD813 (see 2), which makes me think this device is directly powered with something from 12-18 V?! It has also has a connection to both ends of the xtal (3).

How can we modify this to a TCXO version? How do we get the correct voltage?

It is a TFF1017 and it has a 5V supply going in at Pin 16, which is in your picture on the bottom edge of the chip, left pin. You should be able to trace then its origin on the board, likely the chip #1 is generating 5V and the bias voltages for the preamplifier stages.

Edit: the #1 looks like the LS7005 as noted by OH2AUE in the GM-201 mod instructions. Then it should generate 5V at its pin 12, which on your picture is the left-most pin on the top edge.